The Puffin Kids Bed is a 7-inch foam mattress from Nest Bedding made for children and young sleepers, previously known as the BKB. It uses a simple two-layer foam design to provide a supportive, responsive sleep surface for bunk beds, platform beds, trundles, guest rooms, and kids rooms. Construction and materials 7-inch all-foam construction designed for children and growing sleepers. Responsive foam comfort layer provides cushioning and pressure relief. Support foam base layer adds stability and everyday kids mattress support. No-coil design keeps the mattress lighter and easier to handle than many hybrid mattresses. Low-profile height can work well for many bunk beds, trundle beds, daybeds, and platform beds when the bed frame allows. Certifications and origin Foams are CertiPUR-US® certified when listed on the live product page. Built for Nest Bedding by Diamond Mattress. Made with materials selected for a child-focused mattress design. Firmness and sleep fit Designed as a supportive kids mattress rather than a deep-sinking adult plush mattress. Useful for children transitioning from toddler beds to twin, twin XL, or full-size beds. Appropriate for back, side, stomach, and combination sleeping children when the selected size matches the bed setup. Sizes and dimensions Available sizes depend on the current live variant set. Common kids mattress sizes may include Twin, Twin XL, and Full. Confirm exact dimensions against the selected variant and bed frame. Setup, foundation, and care notes Use on a supportive, level foundation, bunk bed platform, slatted base, daybed, trundle, or bed frame approved for foam mattresses. For bunk beds, confirm the mattress height meets the bunk bed manufacturer's guardrail and safety requirements. Allow the mattress to expand after unboxing if shipped compressed. Use a waterproof mattress protector in kids rooms to help protect against spills and accidents. Shipping, trial, and warranty notes Current shipping, trial, return, and warranty details should be confirmed on the live product page and Nest Bedding policy pages. Best uses Kids rooms, bunk beds, trundle beds, guest rooms, and daybeds. Parents looking for a foam kids mattress with certified foams. Families who want a lower-profile mattress for child-friendly room setups. Shoppers comparing the Puffin foam kids mattress with the Lark natural latex kids mattress.